JP2021042806A - Vehicle control device - Google Patents

Abstract

To provide a vehicle control device capable of accurately estimating a degree of wear of a torque transmission member in a continuously variable transmission.SOLUTION: A vehicle control device for controlling a vehicle equipped with a continuously variable transmission includes determination means and estimation means. The determination means determines whether torque input into a torque transmission member of the continuously variable transmission is within a prescribed range or not. The estimation means estimates a degree of wear of the torque transmission member with the usage of a maximum speed ratio of the continuously variable transmission when the torque input into the torque transmission member is within the prescribed range.SELECTED DRAWING: Figure 12

Description

The present disclosure relates to a vehicle control device, and more particularly to a technique for estimating the degree of wear of a torque transmission member in a continuously variable transmission.

Japanese Patent Application Laid-Open No. 2018-25207 (Patent Document 1) warns of belt wear in a continuously variable transmission when the engine speed when the vehicle speed reaches a predetermined value exceeds a preset allowable range. (More specifically, the work vehicle) is disclosed. The continuously variable transmission has an input rotating body and an output rotating body, and the belt is wound around the input rotating body and the output rotating body. The belt functions as a torque transmission member that transmits torque in a continuously variable transmission. The engine torque is input to the input rotating body of the continuously variable transmission, and the torque input to the input rotating body is transmitted to the output rotating body by the torque transmission member.

JP-A-2018-25207

In a belt-type continuously variable transmission, as the wear of the belt progresses, the width of the belt becomes smaller than that in the non-wear state. If the width of the belt becomes excessively small, torque may not be properly transmitted by the belt. Therefore, it is required to estimate the degree of belt wear and replace the belt at an appropriate timing. In the vehicle described in Patent Document 1, the degree of belt wear is estimated based on the engine rotation speed when the vehicle speed reaches a predetermined value. However, when the slip amount of the belt changes in the continuously variable transmission, the relationship between the vehicle speed and the engine rotation speed (and thus the gear ratio of the continuously variable transmission) can change even if the degree of belt wear does not change. Therefore, the technique described in Patent Document 1 cannot always estimate the degree of wear of the torque transmission member (for example, a belt) with sufficient accuracy. There is room for further improvement in order to improve the estimation accuracy of the degree of wear of the torque transmission member in the continuously variable transmission.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a vehicle control device capable of estimating the degree of wear of a torque transmission member in a continuously variable transmission with high accuracy.

The vehicle control device according to the present disclosure is configured to control a vehicle equipped with a continuously variable transmission. The continuously variable transmission includes a torque transmission member that transmits torque. The vehicle control device according to the present disclosure is a determination means for determining whether or not the torque input to the torque transmission member is within the predetermined range, and when the torque input to the torque transmission member is within the predetermined range. It is provided with an estimation means for estimating the degree of wear of the torque transmission member using the maximum gear ratio of the continuously variable transmission.

The gear ratio of the continuously variable transmission changes according to the degree of wear of the torque transmission member. However, when the slip amount of the torque transmission member changes, the gear ratio of the continuously variable transmission can change even if the degree of wear of the torque transmission member does not change. As the torque input to the torque transmission member increases, the torque transmission member tends to become slippery. Further, the force applied to the torque transmission member (for example, the force for holding the torque transmission member) may change depending on the state of the continuously variable transmission. The force applied to the torque transmission member can affect the amount of slippage of the torque transmission member. In the vehicle control device, the maximum gear ratio of the continuously variable transmission corresponds to the gear ratio of the continuously variable transmission when the continuously variable transmission is in the maximum deceleration state. Hereinafter, the gear ratio of the continuously variable transmission when the continuously variable transmission is in the maximum deceleration state and the torque input to the torque transmission member is within a predetermined range may be described as an "estimated parameter". .. The estimation means in the vehicle control device is configured to estimate the degree of wear of the torque transmission member using estimation parameters. The continuously variable transmission is in a constant state (more specifically, the maximum deceleration state), and the torque input to the torque transmission member is within a certain range (more specifically, within a predetermined range). Occasionally, the amount of slippage of the torque transmission member can be made substantially constant. Therefore, the above estimation parameters correlate with the degree of wear of the torque transmission member with high accuracy. By using the above estimation parameters, the estimation means can estimate the degree of wear of the torque transmission member in the continuously variable transmission with high accuracy. The continuously variable transmission has a primary pulley including a movable sheave and a fixed sheave, and is configured so that the movable sheave comes into contact with the stopper in the maximum deceleration state and the sheave spacing of the primary pulley is fixed in terms of hardware. You may. Since the sheave spacing of the primary pulley is constant in terms of hardware, it becomes easy to estimate the degree of wear of the torque transmission member with high accuracy. In a continuously variable transmission, the torque transmission member may be wound around the primary pulley and the secondary pulley.

The above-mentioned predetermined range can be set arbitrarily. The predetermined range may be in the vicinity of 0 Nm (for example, 0 Nm or more and a predetermined value or less). The predetermined range may be one point (for example, 0 Nm).

The estimation means may be configured to estimate that the larger the estimation parameter is, the greater the degree of wear of the torque transmission member. The estimation means may be configured to estimate the degree of wear of the torque transmission member by comparing the current estimation parameters with the estimation parameters in the initial state. The estimation means may be configured to estimate that the greater the amount of change in the estimation parameter from the initial state, the greater the degree of wear of the torque transmission member.

The vehicle control device may further include an execution means for executing a predetermined process when the degree of wear of the torque transmission member estimated by the estimation means exceeds a predetermined threshold value. According to such a configuration, when the degree of wear of the torque transmission member becomes large enough to require some measures, a predetermined process (for example, a measure for dealing with the wear of the torque transmission member) can be executed. The predetermined process may be a notification process that prompts the user to replace the torque transmission member.

The vehicle may be configured to be capable of transmitting power generated by a power source (for example, an engine) mounted on the vehicle to the drive wheels of the vehicle through a plurality of types of routes. The plurality of types of paths may include a first path that does not pass through the continuously variable transmission and a second path that passes through the continuously variable transmission.

According to the present disclosure, it is possible to provide a vehicle control device capable of estimating the degree of wear of a torque transmission member in a continuously variable transmission with high accuracy.

It is a figure which shows the structure of the vehicle to which the vehicle control device which concerns on embodiment of this disclosure is applied. It is a figure which shows the mechanical structure of the power transmission device shown in FIG. It is sectional drawing which shows the detail of the structure of the primary pulley and the belt in the continuously variable transmission (CVT) of the power transmission device shown in FIG. It is a figure which shows the power transmission path (first path) in the GD mode of the vehicle which concerns on embodiment of this disclosure. It is a figure which shows the power transmission path (second path) in the BD mode of the vehicle which concerns on embodiment of this disclosure. It is a figure for demonstrating Nin control when the vehicle which concerns on embodiment of this disclosure is traveling in BD mode. It is a graph which shows the relationship between the mileage and the wear amount of a belt about the vehicle which concerns on embodiment of this disclosure. It is a figure which shows an example of the state in which the width of the belt in the CVT shown in FIG. 3 is excessively small. It is a graph which shows the relationship between the maximum gear ratio of the CVT in the initial state, and the input torque in the vehicle which concerns on embodiment of this disclosure. It is a graph which shows the relationship between the mileage and the maximum gear ratio when the input torque of a CVT is 0 about the vehicle which concerns on embodiment of this disclosure. It is a figure which shows an example of the wear amount map. It is a flowchart for demonstrating the process which concerns on the belt wear diagnosis executed by the vehicle control apparatus which concerns on embodiment of this disclosure.

Embodiments of the present disclosure will be described in detail with reference to the drawings. In the figure, the same or corresponding parts are designated by the same reference numerals and the description thereof will not be repeated. Hereinafter, the electronic control unit will be referred to as an "ECU".

FIG. 1 is a diagram showing a configuration of a vehicle to which the vehicle control device according to this embodiment is applied. With reference to FIG. 1, the vehicle 1 includes an engine 100, a power transmission device 200, an ECU 500, an input device 600, and a notification device 700. The engine 100 is configured to generate power for the vehicle 1 to travel. The power transmission device 200 is configured to transmit the power output from the engine 100 to the drive wheels of the vehicle 1. The ECU 500 is configured to control the vehicle 1. The vehicle 1 may be a hybrid vehicle (HV) capable of traveling by using both the output of the engine 100 and the electric power stored in the power storage device (not shown), or the vehicle 1 may be a power for traveling only the engine 100. It may be the source vehicle (generally also referred to as a "hybrid vehicle"). The drive system of the vehicle 1 may be any of front-wheel drive, rear-wheel drive, and four-wheel drive. The ECU 500 according to this embodiment corresponds to an example of the "vehicle control device" according to the present disclosure.

The ECU 500 includes a processor 510, a RAM (Random Access Memory) 520, and a storage device 530. As the processor 510, for example, a CPU (Central Processing Unit) can be adopted. The RAM 520 functions as a working memory for temporarily storing data processed by the processor 510. The storage device 530 is configured to be able to store the stored information. The storage device 530 includes, for example, a ROM (Read Only Memory) and a rewritable non-volatile memory. When the processor 510 executes the program stored in the storage device 530, various controls of the vehicle 1 are executed. Note that various controls are not limited to software processing, but can also be processed by dedicated hardware (electronic circuits). Further, the number of processors included in the ECU 500 is arbitrary, and processors may be prepared for each predetermined control.

The input device 600 is a device that receives input from the user. The input device 600 is operated by the user and outputs a signal corresponding to the user's operation to the ECU 500. The communication method may be wired or wireless. Examples of the input device 600 include various switches, various pointing devices, a keyboard, and a touch panel. The input device 600 may be a smart speaker or an operation unit of a car navigation system.

The notification device 700 is configured to perform a predetermined notification process to the user (for example, the occupant of the vehicle 1) when requested by the ECU 500. The notification device 700 may include at least one of a display device (for example, a touch panel display), a speaker (for example, a smart speaker), and a lamp (for example, a MIL (fault warning light)). The notification device 700 may be a meter panel, a head-up display, or a car navigation system.

The vehicle 1 further includes an accelerator sensor 511, a brake sensor 512, a shift lever 513a, a shift position sensor 513, and a vehicle speed sensor 514. The accelerator sensor 511 outputs a signal to the ECU 500 according to the accelerator operation amount (for example, the amount of depression of the accelerator pedal (not shown)). The accelerator operation amount indicates the degree of acceleration required of the vehicle 1 by the driver. The brake sensor 512 outputs a signal to the ECU 500 according to the amount of brake operation (for example, the amount of depression of a brake pedal (not shown)). The amount of brake operation indicates the strength of braking required of the vehicle 1 by the driver. The shift position sensor 513 outputs a signal to the ECU 500 according to the position of the shift lever 513a of the vehicle 1 (for example, any of N (neutral), R (reverse), D (drive), and P (parking)). .. The vehicle speed sensor 514 outputs a signal corresponding to the vehicle speed (that is, the traveling speed of the vehicle 1) to the ECU 500.

Any internal combustion engine can be adopted as the engine 100, but in this embodiment, a reciprocating engine is adopted. Combustion energy is generated by burning the air-fuel mixture in a cylinder (not shown) included in the engine 100. This combustion energy is converted into kinetic energy by a piston (not shown) in the cylinder, and the crankshaft (not shown) of the engine 100 rotates.

The engine 100 includes a throttle valve 531, a fuel injection device 532, and an ignition device 533. The throttle valve 531 is provided in the intake passage of the engine 100 and functions as an intake throttle valve. The throttle valve 531 is configured so that the flow rate of air flowing in the intake passage can be adjusted. The fuel injection device 532 includes an injector that injects fuel supplied from a fuel tank (not shown). The fuel injection method may be in-cylinder injection, port injection, or a combination of in-cylinder injection and port injection. The ignition device 533 includes a spark plug that ignites the air-fuel mixture in the cylinder.

The engine 100 further includes an engine cooling water temperature sensor 501, an air flow meter 502, and an engine rotation speed sensor 503. The engine cooling water temperature sensor 501 outputs a signal to the ECU 500 according to the temperature of the cooling water for cooling the engine 100 (for example, the cooling water flowing through the water jacket formed in the cylinder block of the engine 100). The air flow meter 502 outputs a signal to the ECU 500 according to the flow rate of the air flowing in the intake passage of the engine 100. The engine rotation speed sensor 503 outputs a signal to the ECU 500 according to the rotation speed (hereinafter, also referred to as “engine rotation speed”) of the output shaft (that is, the crankshaft described above) of the engine 100.

The power transmission device 200 includes a first CVT rotation speed sensor 521, a second CVT rotation speed sensor 522, a first oil pressure sensor 523, a second oil pressure sensor 524, an oil temperature sensor 525, and a hydraulic actuator 540.

The first CVT rotation speed sensor 521 outputs a signal corresponding to the rotation speed of the primary pulley 51 (see FIG. 2) of the CVT 50, which will be described later, to the ECU 500. The second CVT rotation speed sensor 522 outputs a signal to the ECU 500 according to the rotation speed of the secondary pulley 52 (see FIG. 2) of the CVT 50, which will be described later.

The hydraulic actuator 540 includes a hydraulic circuit, an oil pump for pumping oil to the hydraulic circuit, an electric motor for driving the oil pump, and a plurality of control valves provided in the hydraulic circuit (none of which are shown). The plurality of control valves include a switching valve for switching the oil passage and a pressure regulating valve (for example, a linear solenoid valve) for adjusting the oil pressure. The hydraulic actuator 540 applies the oil pressure adjusted by the pressure regulating valve to the brake B1, the first clutch C1, the second clutch C2, the lockup clutch 10, the sleeve 40a, the movable sheave 51b, and the movable sheave 52b (see FIG. 2). It is configured to supply each of. By controlling the hydraulic actuator 540, the ECU 500 can individually control the flood pressure supplied to each device. The first oil pressure sensor 523 outputs a signal corresponding to the oil pressure supplied to the movable sheave 51b to the ECU 500. The second oil pressure sensor 524 outputs a signal corresponding to the oil pressure supplied to the movable sheave 52b to the ECU 500. The oil temperature sensor 525 outputs a signal to the ECU 500 according to the temperature of the oil flowing through the hydraulic circuit.

FIG. 2 is a diagram showing a mechanical structure of the power transmission device 200. In FIG. 2, the lines AX1, AX2, AX3, AX4, and AX5 show axes parallel to each other.

With reference to FIG. 1 and FIG. 2, the power transmission device 200 includes an input shaft 11 arranged on the line AX1, a primary shaft 12, a shaft 13, a first drive gear 14, a torque converter 20, and a planetary gear. It includes 30, a synchronizer 40, a continuously variable transmission (hereinafter, also referred to as “CVT”) 50, a brake B1 (for example, a brake band), a first clutch C1 and a second clutch C2.

The input shaft 11 of the power transmission device 200 is connected to the crankshaft of the engine 100. The torque converter 20 includes a lockup clutch 10, a pump impeller 21, a turbine runner 22, and a stator 23. The input shaft 11 is connected to the pump impeller 21 of the torque converter 20. The turbine runner 22 is arranged to face the pump impeller 21 and is connected to the primary shaft 12. The inside of the torque converter 20 is in an oil-tight state filled with oil. The stator 23 is connected to a one-way clutch (not shown) supported by the case 200a and is configured to control the flow of oil between the pump impeller 21 and the turbine runner 22. The lockup clutch 10 is controlled by the ECU 500. The connection state between the input shaft 11 and the primary shaft 12 changes according to the state of the lockup clutch 10 (for example, open / half-clutch / engagement). For example, when the lockup clutch 10 is engaged, the input shaft 11 and the primary shaft 12 are directly connected.

The CVT 50 is a belt-type continuously variable transmission including a primary pulley 51, a secondary pulley 52, and an endless belt 53. The primary pulley 51 is located on the input side of the CVT 50 and is connected to the primary shaft 12 so as to rotate integrally with the primary shaft 12. The secondary pulley 52 is located on the output side of the CVT 50 and is connected to the secondary shaft 61 so as to rotate integrally with the secondary shaft 61. The belt 53 is wound around the primary pulley 51 and the secondary pulley 52. In this embodiment, a metal belt (for example, a steel belt) is adopted as the belt 53. However, the present invention is not limited to this, and a dry composite belt whose outside is covered with rubber can also be adopted as the belt 53. The belt 53 according to this embodiment corresponds to an example of the "torque transmission member" according to the present disclosure. The torque transmission member is not limited to the belt, but may be a chain.

Each of the primary pulley 51 and the secondary pulley 52 is a variable groove width pulley configured so that the width of the V groove on which the belt 53 is hung can be changed. When the width of the V-groove becomes wide, the belt 53 hangs at a position close to the rotation center of the pulley. As a result, the winding diameter of the belt 53 becomes smaller. When the width of the V-groove becomes narrow, the belt 53 hangs at a position close to the outer circumference of the pulley. As a result, the winding diameter of the belt 53 becomes large.

FIG. 3 is a cross-sectional view showing the details of the configuration of the primary pulley 51 and the belt 53. With reference to FIG. 3, the primary pulley 51 includes a fixed sheave 51a and a movable sheave 51b (for example, a slide pulley), and a V groove 51c is formed between the fixed sheave 51a and the movable sheave 51b. The belt 53 hangs on the V groove 51c of the primary pulley 51. A hydraulic chamber 51d is formed on the outside of the movable sheave 51b. When the oil pressure of the hydraulic chamber 51d is increased by the hydraulic actuator 540 (FIG. 1), the movable sheave 51b moves inward (toward the arrow D1 side) and the width of the V groove 51c becomes narrow. On the other hand, when the oil pressure of the hydraulic chamber 51d decreases, the movable sheave 51b moves to the outside (arrow D2 side) due to the tension of the belt 53, and the width of the V groove 51c becomes wider. The width of the V-groove 51c is maximized by moving outward (arrow D2 side) until the movable sheave 51b hits the stopper. When the movable sheave 51b is in contact with the stopper, the sheave spacing (that is, the width of the V groove 51c) of the primary pulley 51 is fixed in terms of hardware.

The belt 53 includes two ring-shaped bands 53a and 53b and an element 53c. Each of the bands 53a and 53b is constructed by laminating, for example, thin steel plates. The element 53c holds the bands 53a and 53b. Both side surfaces of the element 53c are in contact with the fixed sheave 51a and the movable sheave 51b in the V groove 51c.

With reference to FIG. 1 and FIG. 2 again, the secondary pulley 52 also has basically the same configuration as the primary pulley 51 described above. The secondary pulley 52 includes a fixed sheave 52a and a movable sheave 52b (for example, a slides pulley), and a V groove is formed between the fixed sheave 52a and the movable sheave 52b. A force (not shown) acts on the movable sheave 52b in the direction of narrowing the width of the V-groove. When the tension of the belt 53 changes due to the change in the groove width of the primary pulley 51, the groove width of the secondary pulley 52 is also adjusted to a size corresponding to the tension of the belt 53. In order to keep the friction between the secondary pulley 52 and the belt 53 in an optimum state, the groove width of the secondary pulley 52 may be adjusted by the hydraulic actuator 540.

The planetary gear 30 shown in FIG. 2 is a double pinion planetary gear including a carrier CR, a ring gear R, and a sun gear S. The carrier CR rotatably supports each of the pinion P1 that meshes with the sun gear S and the pinion P2 that meshes with the ring gear R. The brake B1 is configured to be able to lock the rotation of the ring gear R with respect to the case 200a. A hollow shaft 13 is connected to the sun gear S. A primary shaft 12 is arranged inside the shaft 13. Each of the primary shaft 12 and the shaft 13 is arranged on the line AX1. The primary shaft 12 is connected to the carrier CR of the planetary gear 30.

The shaft 13 is connected to a clutch device including the first clutch C1. The carrier CR is connected to the shaft 13 via the first clutch C1. A first drive gear 14 is attached to the shaft 13. The first clutch C1 is a gear drive clutch, and is engaged when the vehicle 1 travels in the gear drive mode described later.

The synchronizer 40 includes a sleeve 40a, a first driven gear 41, an input shaft 42, a first gear 43, a second gear 44, an output shaft 45, and a second drive gear 46. The input shaft 42 and the output shaft 45 are arranged on the wire AX2, and the input shaft 42 is arranged inside the hollow output shaft 45. Each of the first driven gear 41 and the first gear 43 is attached to the input shaft 42. Each of the second gear 44 and the second drive gear 46 is attached to the output shaft 45. The first driven gear 41 meshes with the first drive gear 14.

The sleeve 40a is configured to be movable along the axial direction. By moving the sleeve 40a, the connection state between the first gear 43 and the second gear 44 can be switched. By moving the sleeve 40a to a position where it meshes with both the first gear 43 and the second gear 44, the first gear 43 and the second gear 44 are connected. By moving the sleeve 40a to a position where it meshes only with the first gear 43, the first gear 43 and the second gear 44 are separated from each other.

The movable sheave 52b of the secondary pulley 52 is connected to the hollow input shaft 62 via the second clutch C2. The secondary shaft 61 is arranged inside the input shaft 62. Each of the secondary shaft 61 and the input shaft 62 is arranged on the line AX3. The second clutch C2 is a belt drive clutch, and is engaged when the vehicle 1 travels in the belt drive mode described later. When the second clutch C2 is engaged, the torque of the secondary pulley 52 is transmitted to the input shaft 62. The second driven gear 63 is attached to the input shaft 62 and meshes with the second drive gear 46.

The reduction gear device 70 includes an output gear 71 attached to the input shaft 62, a driven gear 72 that meshes with the output gear 71, and a counter shaft 73 attached to the driven gear 72. The counter shaft 73 is arranged on the line AX4.

A final drive gear 81 is attached to the counter shaft 73. The final drive gear 81 meshes with the ring gear 82. The ring gear 82 is arranged outside the case of the differential gear 80 and functions as a final driven gear. The differential gear 80 is configured to transmit the torque of the ring gear 82 to the drive shafts 83L and 83R arranged on the wire AX5. The differential gear 80 rotates the drive shafts 83L and 83R at an appropriate speed. As the drive shafts 83L and 83R rotate, the drive wheels (not shown) attached to the tips of the drive shafts 83L and 83R rotate.

In this embodiment, the ECU 500 is configured to drive the vehicle 1 in a plurality of types of travel modes. More specifically, the ECU 500 is configured to switch between the gear drive mode and the belt drive mode described below depending on the situation.

When the position of the shift lever 513a of the vehicle 1 is D (drive) and the vehicle speed is less than a predetermined value (hereinafter referred to as "Th1"), the ECU 500 controls the power transmission device 200 to control the vehicle. The driving mode of 1 is set to the gear drive mode (hereinafter, also referred to as “GD mode”). FIG. 4 is a diagram showing a power transmission path in the GD mode. With reference to FIG. 4, in the GD mode, the brake B1 and the second clutch C2 are in the open state, the first clutch C1 is in the engaged state, and the sleeve 40a meshes with both the first gear 43 and the second gear 44. To do. As a result, the power transmission device 200 transmits power through a path that does not include the CVT 50 (hereinafter, also referred to as a “first path”) as shown by an arrow P11 in FIG. For example, when the vehicle 1 starts, the power of the engine 100 is transmitted to the counter shaft 73 via the torque converter 20, the primary shaft 12, and the first path (arrow P11). That is, the power of the engine 100 is transmitted to the drive wheels of the vehicle 1 without passing through the CVT 50.

When the vehicle speed becomes Th1 or higher while the vehicle 1 is traveling in the GD mode, the ECU 500 controls the power transmission device 200 to switch the traveling mode of the vehicle 1 to the belt drive mode (hereinafter, also referred to as “BD mode”). FIG. 5 is a diagram showing a power transmission path in the BD mode. With reference to FIG. 5, in the BD mode, the first clutch C1 is in the open state, the second clutch C2 is in the engaged state, and the sleeve 40a does not mesh with the second gear 44, only the first gear 43. To mesh with. As a result, the power transmission device 200 transmits power through a path including the CVT 50 (hereinafter, also referred to as a “second path”) as shown by an arrow P12 in FIG. For example, when the vehicle 1 is traveling at high speed, the power of the engine 100 is transmitted to the counter shaft 73 via the torque converter 20, the primary shaft 12, and the second path (arrow P12). That is, the power of the engine 100 is transmitted to the drive wheels of the vehicle 1 via the CVT 50.

With reference to FIGS. 1 and 2, the ECU 500 controls each of the movable sheaves 51b and 52b through the hydraulic actuator 540, whereby the winding diameter of the belt 53 (and thus the CVT50) with respect to each of the primary pulley 51 and the secondary pulley 52. The gear ratio γ) can be controlled. The rotational speed of the primary pulley 51 (hereinafter, also referred to as “Nin”) has a magnitude corresponding to the engine rotational speed. The rotation speed of the secondary pulley 52 (hereinafter, also referred to as “Nout”) becomes a magnitude corresponding to the vehicle speed. The gear ratio γ of the CVT 50 can be expressed by the ratio of Nin to Nout (= Nin / Nout). The ECU 500 continuously (that is, steplessly) sets the gear ratio γ of the CVT 50 in the range from the minimum gear ratio (hereinafter, also referred to as “γmin”) to the maximum gear ratio (hereinafter, also referred to as “γmax”). Can be changed. γmax corresponds to the gear ratio of the CVT 50 when the CVT 50 is in the maximum deceleration state. When the CVT 50 is in the maximum deceleration state, the width of the V groove 51c (FIG. 3) of the primary pulley 51 is maximum (that is, constant). γmin corresponds to the gear ratio of the CVT 50 when the CVT 50 is in the maximum speed increasing state.

In this embodiment, the ECU 500 determines a target value of Nin (hereinafter, also referred to as “target Nin”) by referring to a map (hereinafter, also referred to as “Nin map”) stored in the storage device 530 in advance. Then, the Nin is controlled to the determined target Nin. The Nin map is information showing, for example, the relationship between the accelerator operation amount, the vehicle speed, and the target Nin.

FIG. 6 is a diagram for explaining Nin control when the vehicle is traveling in the BD mode. With reference to FIG. 6, the line L1 and the line L2 show γmax and γmin in the CVT 50 in the initial state, respectively. When the vehicle 1 is traveling in the BD mode, the target Nin is determined within the range of the region R10. The region R10 is set in a range in which the gear ratio γ is equal to or greater than γmin (line L2) in the initial state and equal to or less than γmax (line L1) in the initial state.

By the way, the belt 53 in the CVT 50 can be worn. In particular, both side surfaces of the element 53c (FIG. 3) in contact with the sheave in the belt 53 are prone to wear. As the wear of the side surface (end face) of the belt 53 progresses, the width of the belt 53 becomes smaller than that in the initial state (that is, the state in which the belt 53 is not worn). FIG. 7 is a graph showing the relationship between the mileage correlated with the usage time of the vehicle 1 and the amount of wear of the belt 53 in the vehicle 1. With reference to FIG. 7, as this graph shows, the longer the mileage of the vehicle 1 (and thus the usage time of the vehicle 1), the more the belt 53 wears. The amount of wear of the belt 53 indicated by the vertical axis of the graph corresponds to the amount of decrease in the width of the belt 53 from the initial state. The amount of wear of the belt 53 corresponds to an example of the degree of wear of the belt 53.

If the width of the belt 53 becomes excessively small, torque may not be properly transmitted by the belt 53 in the CVT 50. FIG. 8 is a diagram showing an example of a state in which the width of the belt 53 is excessively small. With reference to FIG. 8, in this example, the belt 53 hooked on the V-groove 51c of the primary pulley 51 is worn and the belt width becomes excessively small, so that the position of the belt 53 is lowered and the belt 53 is in the V-groove. It is attached to the bottom BM of 51c. When the belt 53 attaches to the bottom BM of the V-groove 51c, the belt 53 has slack, so that the torque cannot be properly transmitted by the belt 53. Hereinafter, the attachment of the belt 53 to the bottom of the V-groove is also referred to as "belt bottom attachment". Belt bottoming is more likely to occur on the primary pulley 51 than on the secondary pulley 52.

With reference to FIG. 1 and FIG. 8, if the degree of wear of the belt 53 is small, the ECU 500 controls the movable sheave 51b through the hydraulic actuator 540 so that the belt 53 does not touch the bottom BM of the V groove 51c. The width of 51c can be adjusted. However, since there is a limit to suppressing the slack of the belt 53 by such control, it is desirable to take countermeasures such as replacing the belt 53 when the degree of wear of the belt 53 becomes large. Therefore, the ECU 500 according to this embodiment estimates the degree of wear of the belt 53 by the method described below, and when the estimated degree of wear of the belt 53 exceeds the threshold value, a countermeasure for the wear of the belt 53 ( For example, it is configured to perform a notification process (prompting to replace the belt 53).

The ECU 500 is configured to estimate the degree of wear of the belt 53 by using γmax when the torque input to the belt 53 is within a predetermined range. In the CVT 50, when the belt thrust (that is, the force for sandwiching the belt 53) increases, the amount of slip of the belt 53 decreases. On the other hand, when the torque input to the belt 53 (hereinafter, also referred to as “input torque”) increases, the amount of slippage of the belt 53 increases. The input torque corresponds to the torque applied to the primary pulley 51. By keeping the CVT 50 in a certain state (more specifically, the maximum deceleration state) and keeping the input torque within a certain range (more specifically, within a predetermined range), the amount of slippage of the belt 53 is roughly reduced. Can be constant. When the slip amount of the belt 53 is constant, the gear ratio γ of the CVT 50 and the degree of wear of the belt 53 correlate with high accuracy.

FIG. 9 is a graph showing the relationship between γmax and the input torque in the CVT 50 in the initial state (that is, the state in which the degree of wear of the belt 53 is 0). FIG. 10 is a graph showing the relationship between the mileage that correlates with the usage time of the vehicle 1 (and by extension, the degree of wear of the belt 53) and γmax when the input torque of the CVT 50 is 0. The data shown in each of FIGS. 7, 9, and 10 are data measured in the same vehicle.

With reference to FIG. 9, in this graph, the larger the input torque of the CVT 50, the larger the γmax. As described above, when the degree of wear of the belt 53 is constant, the input torque in the CVT 50 and γmax have a constant correlation.

With reference to FIG. 10, in this graph, the γmax increases as the mileage of the vehicle 1 increases (that is, as the degree of wear of the belt 53 increases). As described above, when the torque (input torque) input to the belt 53 is constant, the γmax in the CVT 50 and the degree of wear of the belt 53 have a constant correlation.

With reference to FIGS. 1 and 2 again, the ECU 500 is configured to obtain the gear ratio γ based on the outputs of the first CVT rotation speed sensor 521 and the second CVT rotation speed sensor 522, respectively. The ECU 500 can obtain Nin based on the output of the first CVT rotation speed sensor 521. The ECU 500 can obtain Nout based on the output of the second CVT rotation speed sensor 522. The ECU 500 can calculate the gear ratio γ (= Nin / Nout) based on these Nin and Nout.

The ECU 500 is configured to determine whether or not the gear ratio γ is γmax. When the CVT 50 is in the maximum deceleration state, the gear ratio γ becomes γmax. In this embodiment, the ECU 500 determines whether or not the gear ratio γ is γmax by using the ratio of the oil pressure supplied to the movable sheave 51b and the oil pressure supplied to the movable sheave 52b. However, the present invention is not limited to this, and the ECU 500 may determine whether or not the gear ratio γ is γmax based on the target value of the gear ratio γ. Further, the ECU 500 may determine whether or not the gear ratio γ is γmax based on the degree of deviation between the target value of the gear ratio γ and the actually measured value. Further, the ECU 500 may determine whether or not the gear ratio γ is γmax based on the state of the vehicle 1 (for example, vehicle speed, accelerator operation amount, and acceleration) and the traveling environment (for example, road gradient). ..

The ECU 500 is configured to determine whether or not the input torque of the CVT 50 is within a predetermined range (hereinafter, also referred to as “range ΔTq”). The range ΔTq is arbitrary as long as the slip amount of the belt 53 is narrow enough not to fluctuate significantly. The range ΔTq may be a predetermined value or less, or may be a predetermined value (that is, one point). In this embodiment, the range ΔTq is set to around 0 (for example, 0 Nm or more and 30 Nm or less). In this embodiment, no torque is applied to the primary pulley 51 when the vehicle 1 is traveling in the GD mode (see FIG. 4). Therefore, the ECU 500 determines that the input torque of the CVT 50 is within the range ΔTq (that is, near 0) when the vehicle 1 is traveling in the GD mode. On the other hand, when the vehicle 1 is traveling in the BD mode, the ECU 500 obtains the input torque of the CVT 50 based on the accelerator operation amount and the rotation speed of the engine 100, and whether or not the obtained input torque is within the range ΔTq. To judge. The ECU 500 can obtain the input torque of the CVT 50 by using, for example, a map showing the relationship between the accelerator operation amount, the rotation speed of the engine 100, and the input torque of the CVT 50. However, the ECU 500 is not limited to this, and the ECU 500 includes the accelerator operation amount, the acceleration of the vehicle 1, the operating state of the engine 100 (for example, the engine rotation speed and the fuel injection amount), the state of the torque converter 20, and the driving environment of the vehicle 1 (for example,). It may be determined whether or not the input torque of the CVT 50 is within the range ΔTq based on at least one of the road gradients).

When the ECU 500 determines that the gear ratio γ is γmax and the input torque of the CVT 50 is within the range ΔTq, the ECU 500 shifts gears based on the outputs of the first CVT rotation speed sensor 521 and the second CVT rotation speed sensor 522. It is configured to find the ratio γ. The gear ratio γ thus obtained is γmax when the input torque of the CVT 50 is within the range ΔTq, and is also referred to as “ΔTq−γmax” below. In this embodiment, ΔTq−γmax corresponds to an example of an “estimated parameter”.

The ECU 500 seeks the degree of dissociation between ΔTq-γmax (hereinafter, also referred to as “initial ΔTq-γmax”) of the CVT50 in the initial state and ΔTq-γmax (hereinafter, also referred to as “current ΔTq-γmax”) of the current CVT50. It is composed of. In this embodiment, the difference between the initial ΔTq-γmax and the current ΔTq-γmax (hereinafter, also referred to as “Δγmax”) is adopted as a parameter indicating the degree of deviation between the initial ΔTq-γmax and the current ΔTq-γmax. The initial ΔTq−γmax is stored in the storage device 530 in advance. The larger Δγmax, the larger the degree of divergence. However, the present invention is not limited to this, and a ratio may be adopted instead of the difference. The closer the ratio is to 1, the smaller the degree of divergence.

In this embodiment, information indicating the relationship between Δγmax and the wear amount of the belt 53 (hereinafter, also referred to as “wear amount map”) is stored in the storage device 530 in advance. The ECU 500 estimates the wear amount of the belt 53 (hereinafter, also referred to as “belt wear amount”) from Δγmax with reference to the wear amount map. When the belt wear amount estimated as described above exceeds a predetermined threshold value (hereinafter, referred to as "threshold value X"), the ECU 500 also includes a countermeasure for wear of the belt 53 (hereinafter, also referred to as "wear countermeasure"). Is configured to perform). As the amount of belt wear increases, the winding diameter of the belt 53 with respect to each of the primary pulley 51 and the secondary pulley 52 decreases, so that the possibility of belt bottoming (see, for example, FIG. 8) increases. In this embodiment, the boundary value between the amount of belt wear that does not cause belt bottoming and the amount of belt wear that may cause belt bottoming is set as the threshold value X. Such a threshold value X is obtained in advance by an experiment or a simulation and stored in the storage device 530. However, the threshold value X is not limited to the above. The threshold value X may be determined in consideration of the occurrence of defects other than belt bottoming due to an increase in the amount of belt wear (for example, deterioration in performance, strength, or drivability in vehicle 1). The threshold value X may be a fixed value or may be variable depending on the situation.

FIG. 11 is a diagram showing an example of a wear amount map. With reference to FIG. 11, line L10 shows a wear map. In this wear amount map, when Δγmax exceeds the threshold value Y, the wear amount of the belt 53 exceeds the threshold value X.

The wear handling measure executed by the ECU 500 in this embodiment is a notification process for urging the user to replace the belt 53. The ECU 500 can execute the notification process by controlling the notification device 700. The notification process to the user is optional, and may be notified by a display on a display device (for example, display of information by characters or images), may be notified by a sound (including voice) by a speaker, or a predetermined value. The lamp may be turned on (including blinking).

The wear countermeasure is not limited to the above notification process, and other wear countermeasures may be adopted in addition to or in place of the above notification process. The wear countermeasures executed by the ECU 500 may be to change the map (for example, the target Nin or the transmission line) used for controlling the CVT 50 so that the belt bottoming does not occur. The wear countermeasures executed by the ECU 500 are to reduce the target value of the gear ratio γ when each of the primary pulley 51 and the secondary pulley 52 is stopped (hereinafter, also referred to as “target gear ratio when stopped”). There may be. When the wear amount of the belt 53 is equal to or less than the threshold value X, the ECU 500 sets the target gear ratio at the time of stopping to γmax, and when the wear amount of the belt 53 exceeds the threshold value X, the target gear ratio at the time of stop is set to a value smaller than γmax. It may be configured to do so. The wear countermeasures executed by the ECU 500 may be to increase the hydraulic pressure supplied by the ECU 500 to the movable sheave 51b of the primary pulley 51 more than usual. At this time, the ECU 500 may prioritize the hydraulic control of the movable sheave 51b over other hydraulic controls. The wear countermeasures executed by the ECU 500 may be to increase the frequency of foreign matter discharge processing of the hydraulic circuit. The ECU 500 may be configured to execute the foreign matter discharge processing of the hydraulic circuit by controlling each control valve provided in the hydraulic circuit. The wear countermeasures executed by the ECU 500 tell the storage device 530 that an abnormality has occurred in the belt 53 by turning on the value (initial value is OFF) of the diagnosis (self-diagnosis) flag in the storage device 530. It may be to record.

FIG. 12 is a flowchart for explaining a process related to wear diagnosis of the belt 53 executed by the ECU 500 according to this embodiment. The process shown in this flowchart is repeatedly executed in a predetermined diagnosis period, and ends when it is determined that the belt wear amount exceeds the threshold value X in the diagnosis period. The above-mentioned diagnosis period may be a period from the start of use of the CVT 50 to the end of the use of the CVT 50, or may be an arbitrary period set by the user.

In step 11 (hereinafter, also simply referred to as “S”) 11 with reference to FIG. 12 together with FIGS. 1 and 2, the ECU 500 determines whether or not the traveling mode of the vehicle 1 is the BD mode. The ECU 500 may determine whether or not the traveling mode of the vehicle 1 is the BD mode based on the outputs of the first CVT rotation speed sensor 521 and the second CVT rotation speed sensor 522. When the traveling mode of the vehicle 1 is the BD mode (YES in S11), the process proceeds to S12. In S12, the ECU 500 determines whether or not the input torque of the CVT 50 is within the range ΔTq (that is, near 0). The ECU 500 obtains the input torque of the CVT 50 based on, for example, the accelerator operation amount and the rotation speed of the engine 100, and determines whether or not the obtained input torque is within the range ΔTq. If the input torque of the CVT50 is within the range ΔTq (YES in S12), the process proceeds to S13, and if the input torque of the CVT50 is not within the range ΔTq (NO in S12), the process returns to S11. ..

In this embodiment, when the traveling mode of the vehicle 1 is not the BD mode, the traveling mode of the vehicle 1 is the GD mode. When the vehicle 1 is traveling in the GD mode, the input torque of the CVT 50 is within the range ΔTq (that is, near 0). Therefore, when the traveling mode of the vehicle 1 is not the BD mode (NO in S11), the process proceeds to S13 without going through S12.

In S13, the ECU 500 determines whether or not the gear ratio γ is γmax. The ECU 500 determines whether or not the gear ratio γ is γmax by using, for example, the ratio of the oil pressure supplied to the movable sheave 51b and the oil pressure supplied to the movable sheave 52b. When the gear ratio γ is γmax (YES in S13), the process proceeds to S14, and when the gear ratio γ is not γmax (NO in S13), the process returns to S11.

In S14, the ECU 500 acquires the gear ratio γ based on the outputs of the first CVT rotation speed sensor 521 and the second CVT rotation speed sensor 522, respectively. The gear ratio γ acquired by the ECU 500 in S14 corresponds to ΔTq−γmax. Subsequently, in S15, the ECU 500 obtains Δγmax from the ΔTq−γmax obtained in S14, and estimates the belt wear amount based on the obtained Δγmax and the wear amount map in the storage device 530. Subsequently, the ECU 500 determines in S16 whether or not the estimated belt wear amount exceeds the threshold value X.

When it is determined that the belt wear amount estimated in S15 does not exceed the threshold value X (NO in S16), the process returns to S11. On the other hand, when it is determined that the belt wear amount estimated in S15 exceeds the threshold value X (YES in S16), the ECU 500 performs a predetermined wear countermeasure (for example, the user replaces the belt 53) in S17. Notification processing) is executed. When the process of S17 is performed, the series of processes of FIG. 12 is completed.

As described above, the ECU 500 is configured to determine whether or not the torque input to the belt 53 of the CVT 50 is within the range ΔTq (S11 and S12 in FIG. 12). The ECU 500 is configured to estimate the degree of wear of the belt 53 using ΔTq−γmax (that is, γmax when the torque input to the belt 53 is within the range ΔTq) (S14 and S15 in FIG. 12). .. The ECU 500 according to this embodiment functions as a "determination means" and an "estimation means" according to the present disclosure.

When the CVT 50 is in the maximum deceleration state and the torque input to the belt 53 is within a predetermined range (for example, the range ΔTq), it is considered that the slip amount of the belt 53 is substantially constant. Therefore, it is considered that ΔTq−γmax correlates with the degree of wear of the belt 53 with high accuracy. By using such ΔTq−γmax, the ECU 500 can estimate the degree of wear of the belt 53 in the CVT 50 with high accuracy.

The ECU 500 is configured to perform wear countermeasures when the degree of wear of the belt 53 estimated as described above exceeds a predetermined threshold value X. According to such a configuration, when the degree of wear of the belt 53 becomes large, wear countermeasures can be executed. The ECU 500 according to this embodiment functions as an "execution means".

The ECU 500 in the above embodiment is configured to determine that the amount of belt wear is large (more specifically, it exceeds the threshold value X) when Δγmax exceeds the threshold value Y (FIG. 11). However, the present invention is not limited to this, and the ECU 500 may be configured to determine that the amount of belt wear is large when ΔTq−γmax is equal to or greater than a predetermined value.

The ECU 500 in the above embodiment is configured to estimate whether the belt wear amount is large or small (more specifically, whether or not the threshold value X is exceeded). However, the present invention is not limited to this, and the ECU 500 may be configured to estimate the amount of belt wear in three or more stages (for example, large / medium / small) using a plurality of threshold values. Further, the ECU 500 may be configured to estimate the amount of belt wear according to Δγmax or ΔTq−γmax using a map created in advance.

In the process of FIG. 12, when the gear ratio γ is γmax (YES in S13), the belt wear amount is estimated (S15). The ECU 500 may intentionally set the gear ratio γ to γmax when the estimated frequency of belt wear (that is, the estimated number of times per unit time) is equal to or less than a predetermined value. For example, the ECU 500 may change the target value of the gear ratio γ so that the gear ratio γ becomes γmax when the vehicle 1 travels at a low speed in the GD mode (FIG. 4). Further, the ECU 500 may change the target value of the gear ratio γ so that the gear ratio γ becomes γmax when the vehicle 1 stops in the BD mode (FIG. 5).

The configuration of the vehicle to which the vehicle control device is applied is not limited to the configuration shown in FIG. For example, in the above embodiment, the ECU 500 is configured to be able to change the path for transmitting the power of the engine 100 to the drive wheels of the vehicle 1. The vehicle 1 in the above embodiment has a first route (see arrow P11 in FIG. 5) and a second route (see arrow P12 in FIG. 5). The ECU 500 is configured to select either a first path that does not pass through the CVT 50 or a second path that passes through the CVT 50, and transmits the power of the engine 100 to the drive wheels of the vehicle 1 by the selected path. To. However, the present invention is not limited to this, and the vehicle does not have to have the first route. The vehicle and its control device may be configured to transmit the power of the engine 100 to the drive wheels of the vehicle only by the second path. In such a vehicle, since the traveling mode is always the belt drive mode, the determination of S11 in the process of FIG. 12 can be omitted.

The vehicle to which the vehicle control device is applied may be an electric vehicle (EV) that does not have an engine (internal combustion engine) and is driven by a motor. In the power transmission device 200 shown in FIG. 2, a traveling motor of an electric vehicle may be connected to the primary shaft 12 instead of the torque converter 20.

As the torque transmission member of the CVT 50, a chain may be adopted instead of the belt 53. Rocker pins in the chain can wear as well as element 53c (FIG. 3). The ECU 500 can estimate the degree of wear of the chain (for example, the amount of wear of the rocker pin) by a method similar to the method for estimating the amount of belt wear described above.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the embodiment described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 vehicle, 10 lockup clutch, 11 input shaft, 12 primary shaft, 13 shaft, 14 first drive gear, 20 torque converter, 21 pump impeller, 22 turbine runner, 23 stator, 30 planetary gear, 40 synchronizer, 40a sleeve, 41 1st driven gear, 42 input shaft, 43 1st gear, 44 2nd gear, 45 output shaft, 46 2nd drive gear, 51 primary pulley, 51a fixed sheave, 51b movable sheave, 51c V groove, 51d hydraulic chamber, 52 secondary Pulley, 52a fixed sheave, 52b movable sheave, 53 belt, 53a band, 53c element, 61 secondary shaft, 62 input shaft, 63 second driven gear, 70 reduction gear device, 71 output gear, 72 driven gear, 73 counter shaft, 80 differential Gear, 81 Final drive gear, 82 ring gear, 83L, 83R drive shaft, 100 engine, 200 power transmission device, 200a case, 500 ECU, 501 engine cooling water temperature sensor, 502 airflow meter, 503 engine rotation speed sensor, 510 processor, 511 Accelerator sensor, 512 brake sensor, 513 shift position sensor, 513a shift lever, 514 vehicle speed sensor, 520 RAM, 521 first CVT rotation speed sensor, 522 second CVT rotation speed sensor, 523 first hydraulic sensor, 524 second hydraulic sensor, 525 Oil temperature sensor, 530 storage device, 53 1 throttle valve, 532 fuel injection device, 533 ignition device, 540 hydraulic actuator, 600 input device, 700 notification device, B1 brake, BM bottom, C1 1st clutch, C2 2nd clutch, CR Carrier, P1, P2 pinion, R ring gear, S sun gear.

Claims (1)

A vehicle control device that controls a vehicle equipped with a continuously variable transmission.
The continuously variable transmission includes a torque transmission member that transmits torque.
A determination means for determining whether or not the torque input to the torque transmission member is within a predetermined range, and
An estimation means for estimating the degree of wear of the torque transmission member using the maximum gear ratio of the continuously variable transmission when the torque input to the torque transmission member is within the predetermined range.
A vehicle control device.

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